Telephone system.



H. P. CLAUSEN.

TELEPHONE SYSTEM.

APPLICATION r'luid OCT. 29, 1911.

1,298,293. Patented Mar. 25,1919.

- L I /nvenlor:

Hen/y PC/auaen.

by WM UNITED STATES PATENT OFFICE.

HENRY P. GLAUSEN, OF MOUNT VERNON, NEW YORK, ASSIGNOR TO WESTERNELECTRIO COMPANY, INCORPORATED, OF NEW YORK, N. Y., ACO'RPORATION OF NEWYORK.

TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented Mar. 25, 1919.

Application filed October 29, 1917. Serial No. 199,037.

To all whom it may concern:

Be it known that I, HENRY P. GLAUSEN, a citizen of the United States,residin at Mount Vernon, in the county of Westc ester and State of NewYork, have invented certain new and useful Improvements in TelephoneSystems, of which the following is a full, clear, concise, and exactdescription.

This invention relates to telephone systems, and more particularly tocircuits controlling the release of automatic selective switches used insuch systems.

In automatic telephone systems means have been provided for permittingthe called party, by performing some act, to tie up the connector switchattached to his line in such a way that the calling party, even thoughhe replaces his receiver on the switchhook, cannot become disassociatedwith the called partys line.

This same act performed by the called subscriber operates a signal atthe central ofiice for notifying an attendant thereat to trace back theconnection and find the call ing line. This sort of an arrangement isparticularly useful in connection with fire calls, calls from lines introuble, or for 10- eating the source of calls maliciously originated.

Heretofore the means supplied have always consisted in setting up aspecial circuit condition in the connector switch which operates asignal associated with the connector switch. This results inconsiderable work in tracing back and locating the calling line in amultiofiice system.

The object of this invention is to provide means for the called party tolock up the connection and cause the operation of a signal associatedwith a group of lines containing the calling line. In this way thecalling line may be very quickly found by an attendant when he respondsto the signal.

It is believed that the invention will be understood by tracing a callfrom a calling subscriber to a called subscriber, reference being madeto the accompanying drawing, which diagrammatically represents circuitsand apparatus involved in establishing such a connection. In order tosimplify the disclosure only a calling and called subscribers line, aline switch associated with each line and a connector switch arerepresented in the drawing, but to one skilled in the art it will "bereadily seen that any desired number of selector switches may be used toestablish a connection between the two subscribers lines withoutdeparting from the spirit of this invention.

When the subscriber at substation A removes his receiver from theswitch-hook, a circuit is closed from grounded battery,

right-hand winding of relay 1, outer left hand armature and back contactof magnet 2, apparatus at substation A, inner left-hand armature andback contact of relay 2 to ground. Relay 1 completes a circuit fromgrounded battery, hi gh-resistance right-hand winding of magnet 2,armature and front contact of relay 1 to ground. The energization of thehigh resistance winding of magnet 2 causes this magnet to attract allits armatures, thus operating the plunger 3 to close contact springs 4,5 and 6 to con nect the calling line with the connector switch.

As soon as the contact springs 4 and 5 are closed a circuit is closedfrom grounded battery, left-hand winding of relay 7 contact springs 8and 4, apparatus at substation A, left-hand winding of relay 1, contactsprings 5 and 10, right-hand winding of relay 7 to ground. Relay 7becomes energized and completes a circuit from grounded battery, windingof relay 11, armature and front contact of relay 7 to ground. Relay 11closes a holding circuit for magnet 2 from grounded battery, lowresistance left-hand winding of magnet 2, contact springs 6, enterarmature and front contact of relay 11 to ground.

The energization of magnet 2 opens the original energizing circuit ofthe right-hand winding of relay 1, but this winding is maintainedenergized by a circuit completed through the outer right-hand armatureand front contact of magnet 2, resistance 9 to ground.

The relay 1 is difi'ercntially wound in such a manner that as soon asthe circuit through its left-hand windin is closed, the two windingsoppose each ot er, causing the relay to retract its armatures, thusopening a circuit for a group relay 12 which was closed upon the initialcnergization of the right-hand winding of relay 1. The relay 12 iscommon to a plurality of subscribers lines and is made slow to attractits armatures. It takes such a long time for this relay to attract itsarmature-s that the relay 1 has time to attract and retract itsarmatures in the manner above mentioned before the relay l2 attracts itsarmatures.

The subscriber at substation A now sends out a set of impulses. Inresponse to each impulse the relay 7 deenergizcs and com pletes acircuit from grounded battery. sideswitch arm 13, primary magnet 14,escapement magnet 15, inner armature and front contact of relay 11,armature and back contact of relay 7 to ground. Each energizw tion ofthe primary magnet 14: moves the switch one step in its primarymovement. Relay 11 and magnet 15 are so constructed as to remainenergized during short interruptions in their energizing circuit andtherefore do not release during the transmission of the impulses. Afterthe last impulse, the relay 7 remains energized, thereby opening thecircuit of escapement magnet 15 for a sufficient length of time to causethis magnet to deenergize and move the side-switch arms into theirsecond positions.

A second series of impulses is now sent by the calling subscriber. Eachimpulse causes the denergization of relay 7 in the same manner asbefore, which in turn closes a circuit from grounded battery,side-switch arm 13 (second position), outer left-hand armature and backcontact of test relay 17, winding of secondary magnet 16, winding ofescapement magnet 15. inner armature and front contact of relay 11,armature and back Contact of relay 7 to ground. Each energizetion of thesecondary magnet 16 moves the switch one step in its secondary movement.

After the last impulse of this series is transmitted, magnet 15 isdeenergized in the same manner as before and the side-switch arms aremoved into their third positions.

The brushes 18, 19 and 20 of the connector switch will now be inengagement with terminals 21, 22 and 23 of the desired line. \Ve willfirst assume that the called line is idle.

As soon as the side-switch arm 24 reaches position 3, ground isconnected to the test terminal 23 of the called line, thus renderingthis line nonselectable by other connector switches. This ground alsocloses a circuit from grounded battery, low-resistance left hand windingof magnet 2' of the called substation B, terminal 23 to ground. Theencrgization of this winding is sutlicient to cause the magnet 2' toattract its left-hand armatures but not to attract the plunger of theline switch associated with the called line. Magnet 2' by attracting itsouter lefthand armature places a shunt around the left-hand winding ofrelay 1 and thus prevents this winding from becoming energized. Magnet 2by attracting its leftdiand armatures opens the circuit through therighthand winding of relay 1 and therefore prevents this winding frombecoming energized.

It is therefore obvious that when a line is called, the line switchassociated therewith cannot be operated by the called party rcmoving hisreceiver in answering a call.

The side-switch arm 24 in moving into position 3 also closes a. circuitfrom grounded battery, winding of relay 25, armature and back contact ofrelay 26, side-switch arm 24 to ground. Relay 25 by attracting itsarmaturcs connects the line conductors 27 and 28 to the called line. Theside-switch arm 13 in moving into position 3 closed a circuit for theringing relay 29 from grounded battery, side-switch arm 13. righthandarmature and back contact of relay 31, winding of ringing relay 29,brush 32, interrupter 30 to ground. Every time the brush 32 engages aconducting segment of the interrupter 30, current flows through thiscircuit and energizes ringing relay 29. This relay then closes a circuitfrom a grounded source of ringing current, lower armature and frontcontact of relay 29, line conductor 28. lower armature and front contactof relay 25, brush 19, terminal 22. conductor 32, normal contact 33 ofthe plunger associated with the called line, outer left-hand armatureand front contact of magnet 2, apparatus at substation B, terminal 21,brush 18. upper armature and front contact of relay 25, line conductor27, upper arn'iature and front contact of relay 25) to ground. Thisringing current is intermittently applied to the called line by theoperation of the ringing relay 29. As soon as the called party answersby removing his receiver, and the ringing relay 29 becomes deenergized,suflicient current flows through the line relay 35 to cause this relayto energize. This circuit may be traced from grounded battery, left-handwinding of relay 35, upper armature and back contact of ringing relay 29over the ringing circuit previously described to conductor then throughthe lower armature and back contact of ringing relay 29, right-handwinding of relay 35 to ground. Relay 35 by attracting its right-handarmature closes a circuit from grounded battery, side-switch arm 13,winding of relay 01, front contact and righthand armature of relay 35,olf-normal contact 36 to ground. Relay 31 becomes encrgized and closesat its left-hand armature and front contact. a. locking circuit foritself. Relay 31 by attracting its righthand armature opens the circuitof relay 29. The two subscribers are now connected for conversation.

At the end of conversation after both subscribers have replaced theirreceivers. line relays 7 and 35 become dci ncrgizcd. thus opening thecircuit for relay 11, which de'einergizes and closes a. circuit fromgrounded battery. winding of release magnet 38, off-normal conta t 39,inner armature and back contact of relay 11, armature and back contactof relay 7 to ground. Release magnet 38 becomes energized and returnsthe connector switch to normal in the wellknown manner. Thedeenergization of relay 11 also opens the circuit through the holdingwinding of magnet 2, thus allowing the line switch associated with thecalling line to release. The side-switch arm 24, in leaving its thirdposition when the connector switch is being restored to normal, removesground from the holding winding of magnet 2', thus allowing thearmatures of magnet 2', associated with the called line, to release.

If the called line had been busy, ground would have been found on thetest terminal thereof, so that when the escapemenjt magnet 15 inposition 2 deenergizes after the second series of impulses a circuitwould have been com leted from grounded battery, winding 0 relay 26,contact 43,,winding of test relay 17, side-switch arm 24 (secondposition), brush 20, terminal 23 to ground. Test relay 17 becomesenergized and closes a locking circuit to ground for itself at itsinnerright-hand armature and front contact. At its outer right-hahd armatureand-front contact, it connects the busy signal to the lower lineconductor, thus notifying the calling subscriber that the called line isbusy. The conductors 27 and 28 are not connected to the desired line atthis time due to the circuit of relay 25 being opened at the armatureand back contact of relay 26. The calling subscriber i'e"eiving thisbusy signal hangs up the receiver and brings about the release of theswitches in the manner above described.

We will now assume that while the subscribers are connected forconversation, the called party wishes to find out who is talk ing tohim. The called party will then operate his dial, so as to send out apredetermined number of impulses. Each impulse causes the deenergizationof relay 35, thus closing momentarily the make-before-break contact 40to close a circuit through the slow-to-pull-up relay 41. This relay isso constructed that it has to receive a certain number of impulseswithin a certain period of time before it attracts its plungersufficiently to close the contacts controlled thereby. We will assumethat nine impulses have to be sent. Therefore the called subscriber Bwill dial 9. After the ninth impulse the relay 41 has attracted itsarmature sufficiently to close a locking circuit for itself fromgrounded battery, winding of relay 41, contact springs 49, left-handarmature and front contact of relay 35, to ground. If, while theimpulses are being sent .by the called subscriber, the callingsubscriber should hang up and dener ize relay 7, the

connection would not be bro en down due to s a circuit for relay 11being intermittently closed at the outer left-hand armature and frontcontact of relay 35 while the impulses are being sent.

Relay 41 by operating its contacts reverses the direction of currentflow to the calling line. If, therefore, the calling party still has hisreceiver off the hook, the current flowing through both windings ofdifi'erential relay 1 will now be in such direction as to aid each otherand cause it to attract its armature. Relay 1 will now remain energizeda sufficient length of time to allow the slow-to-pull-up relay 12 toenergize. soon as this relay attracts its armature, it closes a lockincircuit to ground for itself through its rig t-hand armature and frontcontact and key 44. At its left-hand armature and front contact itcloses the circuit for the signal 45. The attendant at the centraloflice hearing this signal is informed that a connection has been lockedu and that the arty initiating the call is in the group of i-nes withwhich the operated signal' is associated. After the attendant hasobtained the desired information, the signal is cleared out bydepressing the key 44.

If the calling party should hang u l'llS receiver after the relay 41 hasoperate the relay 1 will still attract its armature due to the circuitthrough its right-hand wlndmg being closed since the holding circuit ofthe magnet 2 is held closed at the outer armature and front contact ofrelay 11.

The connection is held locked up until the called party replaces hisreceiver, at which time relay 35 deenergizes and opens the eucuits ofrelays 41 and 11, whereupon the switches are released in the same manneras above described.

What is claimed is:

1. In a telephone exchange system, a central office, a calling and acalled subscribers line terminating at said oflice, automatic switchesfor interconnecting said lines, a signal permanently associated withsaid calling line, means for locking said switches in an actuatedposition to maintain an existing condition, and means to operate saidsignal when said lockin means is actuated.

2. In a telephone exc ange system, a central office, groups of callingsubscribers lines terminating at saidv oflice, called subscribers lines,a signal associated with each group of calling lines, automatic switchesfor interconnecting said calling and called lines, means for lockingsaid switches in an actuated position to maintain an existing condition,and means to operate the signal associated with a particular group ofcalling lines when said locking means is actuated to lock the switchesconnecting a callin line of said particular group with a ca ledline.

3. In a telephone exchange system, a central oflice, calling and calledsubscribers lines terminating at said oilice, automatic switches forinterconnecting said lines, a signal associated with said calling lines,a difierential line rela normally associated with each of said callinglines for control ling said signal, means for locking said swltches tomaintain an existing connection between a calling and called line, andmeans for operating the differential relay of the calling line tooperate said signal when said locking means is actuated.

4. In a telephone exchange system, a central oilice, calling and calledsubscribers lines terminating at said oflice, automatic switches forinterconnecting said lines, a signal at the central ofiice associatedwith said calling lines, a, difi'erential line relay permanentlyassociated with each of said calling lines for controlling said signal,means for locking said switches tomaintain an existing connectionbetween a calling and called line, and means for operating thedifferential relay of the calling line to operate said signal when saidlocking means is actuated.

5. In a telephone system, a callin subscribers line, a calledsubscribers me, a central oflice, automatic switches for interconnectingsaid lines, a signal associated with said calling line, a difierentialline relay permanently associated with said calling line for controllinsaid signal, means under the control of the called subscriber forlocking said switches to maintain a connection between said subscriberslines, and means for operating said difl'erential relay to operate saidsignal when said locking means is actuated.

6. In a telephone system, a calling subscribers line, a calledsubscribers line, a central office, automatic switches forinterconnecting said lines, a signal associated with said calling line,a differential line relay normally associated with said calling line forcontrolling said signal, means associated with said called line fortransmitting impulses, means operated by the transmission of aredetermined number of impulses for loc ing said switches to maintain aconnection between said subscribers lines, and means for operating saiddifferential relay to operate said signal when said lockin means isactuated.

In a telephone system, a calling subscribers line, a called subscribersline, a central oflice, automatic switches including a connector switchfor interconnecting sai lines, a si nal associated with said callingline, a difi erential line relay normally associated with said callingline for controllin said signal, means associated with the cello linefor transmitting impulses, and a slowto-pull-up relay at said connectorswitch operated by the transmission of a predetermined number ofimpulses for locking said switches to maintain a connection between saidsubscribers lines, and for operating said differential relay to operatesaid signa 8. In a telephone system, a calling subscribers line, acalled subscribers line, a

central oflice, automatic switches for interconnecting said lines, asignal associated with said calling line, means associated with thecalled line for transmitting impulses, means operated by thetransmission of a predetermined number of impulses for locking saidswitches to maintain a connection between said subscribers lines, andmeans for operating said signal when said locking means is actuated.

9. In a telephone exchange system, a calling and a called subscribersline, switches for interconnecting said lines, means for locking saidswitches in an actuated position, variably operable means forcontrolling the last named means, and a signal actuated when saidswitches are locked.

10. In a telephone exchange system, groups of calling subscribers lines,called subscribers lines, a signal individual to each group of callingsubscribers lines, switches for interconnecting said calling and called.subscribers lines, means for locking said switches in an actuatedposition, and means for operating the signal. individual to the grou ofcalling subscribers lines in which a cal ing line is located when saidswitches are locked.

11. In a telephone exchange system, groups of calling subscribers lines,called subscribers lines, a signal individual to each group of callingsubscribers lines, switches for interconnecting said callin and calledsubscribers lines, means for Iocking said switches in an actuatedposition, variably operable means for controlling said locking means,and means for operating the signal individual to the roup of callingsubscribers lines in which a callin line is located when said switchesare loc ed.

12. In a telephone exchange s stem, a central ofiice, groups of callingsu scribers lines, called subscribers lines, switches forinterconnecting said calling and called subscribers lines, means forlocking said switches in an actuated position, a signal at the centraloflice individual to each group of calling1 subscribers lines, means foroperating t e signal individual to the group of calling subscriberslines in which a calling line is located, and means at the centraloflice for rendering said signal ineffective.

13. In a telephone exchange system, a calling and a called subscribersline, switches for interconnecting said lines, a signal associated withsaid calling line, a differential relay for controlling the operation ofsaid signal, and means for locking said switches in an actuated positionand for reversing the current to aid calling line whereby said relay isactuated to control said si nal. v y

14. n a telephone exchange system, a calling and a called subscribersline, switches for interconnecting said lines, a signal associated withsaid calling line, a differential relay for controlling the operation ofsaid signal, means for locking said switches in an actuated position andfor re- 10 versing the current to said calling line whereby said relayis actuated to control said signal, and variably o erable means forcontrolling the last name means.

In witness whereof, I hereunto subscribe 16 my7name this 24th day ofOctober A. D., 191

HENRY P. CLAUSEN.

